Equipment impressions from Snake Valley

[janoskiss]

Few impressions of some fine scopes and accessories we played with at Snake Valley:

Jodie's 10" + Argonavis (Dave47's old scope) was a big hit. Micheal and Ian (from Tassie) seemed to be having a ball with it finding lots of DSOs. It really helped out with finding planetaries that I could find on the charts but could not distinguish from stars in wide angle EPs due to small angular size.

Big and bigger high-end refractors were great to try out: Stu's Tak 102, Julians AP 130 and Peter's Tak. Very nice crisp images and excellent contrast. BUT I have no refractor fever! I like my Dob. I preferred it on Jupiter to the the AP 130. It's nuts when you think about it. $400 scope vs $17000 scope. I could see more detail in the $400 scope (aperture does rule!), and using high contrast EPs like TV plossl and UO HDs the contrast is very good too (not like the apos of course but respectable). Interestingly the apo that impressed me the most was the smallest one: Stu's 102mm Tak. I did not expect to see so much detail on Saturn through the relatively small aperture.

I was somewhat surprised that all the Naglers I looked through showed stray light on planets: little dancing reflected light ("fairy" as Daniel called it) bouncing around the field in response to any head movement. I don't know how one can pay so much money for Naglers and think that this kind of build/design flaw is acceptable. :shrug:

The piece of equipment I was most impressed with was Daniel's 22mm LVW. Edge performance at f5 was clearly superior to the 19mm Panoptic, certainly the best I've seen. Daniel and even Stu the big Pano-fan can back me up on this one. The LVW 8mm was not quite as good with more geometric aberrations and false colour near the edge, very similar to the Stratus 8mm.

I've been convinced by the superiority of Saxon Dobs (or SkyWatcher Dobs) over the GS, in terms of finish and functionality. 1) The paint on the Saxon OTA is tough, durable and white, much like on good quality whitegoods. The GS has one thin coat of paint in grey/silver colour that peels off easy. It peeled off with the double sided tape when I moved my Telrad. Not a hint of rust on the Saxon. 2) The friction control on the Saxon is far better than the springs on the GS. This is because you have continuous control and you can adjust the tension as you are moving the scope around: one hand on the end of the tube moving it around and the other on the tension handle.

[ving]

go the mights 200mm GSO steve!! :)
theres nothing quite like a well collimated 8"er is there :)
thanks for the write-up :)

sounds like the vixen EP is a hit. you getting one now? ;)

[janoskiss]

Yes there is. Almost forgot to include: 12" GS Dob! I spent a few hours with Ken's 12" Dob while he was mucking around with his 8" EQ imaging setup. The difference on galaxies was quite astounding. On the brighter showpiece objects it is not a huge difference, but on galaxies it is very obvious. Detail I can just make out with averted vision in the 8" is clearly visible in the 12". E.g., spiral arms of the Southern Pinwheel, structure in dust lane in 5128 ("Hamburger), shape of Sombrero, fainter galaxies and galaxy clusters.

But, on the downside, I could not sit down at a 12" and got a sore back (maybe a tall stool would work), and I could not move it by myself. That would be very inconvenient for backyard observing where I constantly move my 8" around with ease, following planets and dodging trees.



Not for a while, but maybe one day, when I have a bigger faster scope where the Panos would not be so good.

[ving]

well yeah, I'd expect a 12"er to perform better on faint fuzzies.... :P

[beren]

Wow some impressive gear :) ive only had a single opportunity to look through a couple of high end refractors which was great but returning to my {X}humble sonotubed 8"newtonian gave me immunity to refractor fever :D interesting call on the naglers , havet noted that problem on mine except for the 6mm Radian :confuse3:

[janoskiss]

You're right about Radians. At least one I tried had the stray light problem too. Probably to a greater degree than the Naglers.

Another thing I should add is that star clusters look absolutely superb in an apo. Stars that tightly focus to sharply defined points of light with no diffraction spikes against a dark background sky are a very impressive sight. Wide views of Saturn among the stars were beautiful.

[matt]

Re; the Nagler and dancing "fairy" light. I get it too when I use the 13mm T6, especially in the 8" f5. There's also a fair bit of scattered light surrounding planets like Jupiter and Saturn. Don't even bother with Venus.

It's also (surprisingly) less forgiving even slightly off-axis, which was a bit of a disappointment at first.

But once you turn it on DSOs then the joy of this EP is revealed and I'm pretty sure that that is it's main function?

John (ausastronomer) can explain why, I'm sure.:thumbsup:

[janoskiss]

No Pentaxes at the camp. I wonder if they suffer from the fairies syndrome too. :confuse3:

[Starkler]

To a small extent on very bright objects yes it can happen.

I beleive the reason for this happening is a reflection from ones eyeball back onto the eye lens (terminology?) of the eyepiece. It appears to be a function of brightness of object viewed, the quality of eyepiece lens coatings, and a large eye lens on the eyepiece.
Cheap ep's with inferior coatings will suffer this to a much greater degree.

As for the Saxon vs GS dob observations, yes the saxon paintwork is far superior. Standard sticky tape holding a bit of paper to my ota being removed resulted in paint comming off with it :(


A scope will always be at its best when balanced. If you can get your scope balance point to be at the altitude hubs, discussions of the pros and cons of springs vs tension handles is probably moot.

I would be very interested to know if anyone critically compared the optical quality of the Saxon vs GS dobs.

[acropolite]

I get the fairies thing too with my 13mm Baader, but careful eye placement eliminates it. I suspect it's just a reflection off the surface of your eye, which is a difficult thing to multicoat, and not a design flaw.

[Dave47tuc]

Just a note Steve,
The AP & Tak, are 5" Apo's. or 130 mm.:)

IMO I disagree. The Apo's were better than any of the Newts. :)

I'm not going to get into it. Each to there own.:)

[janoskiss]

Yeah, I knew that. ;) I edited my post.


Well, I looked at Jupiter through Julian's Apo for about 20 seconds in better than average seeing, and through the Newt for about an hour or two, much of which was in the best seeing, so it was not exactly a fair comparison. :) But I'll be so much happier and wealthier if I believe that the bigger Newts were better than the apos. ;) The apo bug is even worse than aperture fever, in dollar terms. Look at Stu! He has his Tak at long last, but he can hardly afford to feed himself. :rofl:



Come'on Dave! Newt vs SCT vs Apo vs Mak! Dob vs GoTo vs PushTo! :D

:fight:

[janoskiss]

Thanks Phil & Geoff for the lesson! I did not even think of that! I just assumed that it was something inside the EP, like lens edges or retaining rings, that were not properly blackened.

The Meade 6.7mm UWA had this sort of thing too but it was MUCH worse in that EP than in the Nagler or Radian. Ditto 5.2mm ED-2, and the right ocular in my binoviewers. I believe in these more severe cases it was due to flaws in the EP/BVer itself.

OTOH, I never had the problem with my Stratus or Panoptic. It must be the curvature of the exit lens that determines whether it reflects the light back to or away from the pupil. Maybe I should get myself some FMC contact lenses. :D

[Starkler]

Its a shame nobody did a side by side between the saxon and the GS on Joop in good seeing. I think a lot of people would be interested in the results :shrug:

[janoskiss]

There was just too much going on, Geoff. You set out to do something but walking 20-30m from one spot to another you would get distracted by the queue to the apo aimed at Orion, then we had to look at the same in the Celestron 9.25" SCT, then the tour with the Argo etc etc. It was a couple of hours before Stu & I got to try out a couple of EP in my scope because there were so many distractions. There was equipment to drool on everywhere. :D There was a lot of imaging going on too, which meant many scopes were unavailable . We only had two 10" GS Dobs there actually. Jodie's and Dave P's, both of which were in high demand throughout the two nights.

I'm sure we'll get around to doing the comparison one day.

[Starkler]

I can imagine Steve :lol:

Even with the three or four of us in the group i observe with theres a lot of running back and forth between scopes, yacking on and not too much hardcore observing :)

[Twokids]

Sadly, Daniel and I are on opposite sides of the city so other than at these camps, it's hard to organise a side by side comparison. If Daniel's ever down this way though, I'm happy to volunteer my scope. It would be interesting to know the results.

[davidpretorius]

best view for me: orion through a 19mm??? pano in paul's c9.25. never seen the tendrils that seem to twist before, that was awesome.

peter's tak was fantastic on saturn, along with julian's refractor on friday night.

ken's 12" on sombrero was awesome!!!!

loved daniel saxon with the ed80 strapped to it, fantastic looking setup!

[davidpretorius]

also, panoptics are great!